Using Receive Diversity to Extend Standby Time in QPCH Mode

• US 20100210321A1
• Filed: 08/06/2009
• Published: 08/19/2010
• Est. Priority Date: 04/08/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kurapati, Nagabhushana Rao, Tu, Kuang-Hsuan
• Granted Patent: US 8,649,306 B2
• Time in Patent Office: Days
• US Class Current: 455/574
• CPC Class Codes: H04B 7/0882 using post-detection diversity
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The standby time of a CDMA cell phone is extended by using two receive chains to monitor the Quick Paging Channel (QPCH) when the signal-to-noise ratio falls within a predetermined range. Monitoring the QPCH saves battery power by obviating the need to monitor the general paging message unless quick paging (PI) bits are set. The QPCH is not monitored, however, in noisy environments where PI bits are incorrectly detected causing the paging message to be needlessly monitored. Power is saved by monitoring the QPCH in noisier environments without increasing the incorrect detection rate. Incorrect detection is reduced in the predetermined range by using an additional receive chain to achieve receive diversity. Although additional power is consumed by the second receive chain in the predetermined range, the power saved by not demodulating the paging message at each slot more than compensates for the additional power consumed by the second receive chain.

Claims

1. A method comprising:

(a) receiving a signal;

(b) determining a signal-to-noise ratio of the signal;

(c) determining whether a quick paging channel is transmitted at a half rate or a full rate; and

if the signal-to-noise ratio falls within a predetermined range, and if the quick paging channel is transmitted at the full rate, performing the step of;

(d) demodulating a first quick paging bit from the quick paging channel received through both a first receive chain and a second receive chain.

2. The method of claim 1, further comprising:

if the signal-to-noise ratio is above the predetermined range, and if the quick paging channel is transmitted at the full rate, performing the steps of;

(e) providing no power to the second receive chain; and

(f) demodulating a second quick paging bit from the quick paging channel received through the first receive chain.

3. The method of claim 1, further comprising:

if the signal-to-noise ratio is below the predetermined range, and if the quick paging channel is transmitted at the full rate, performing the steps of;

(e) providing no power to the second receive chain; and

(f) demodulating a general paging message from a regular paging channel received through the first receive chain.

4. The method of claim 1, wherein the signal-to-noise ratio is the signal-to-noise ratio of a pilot channel.

5. An apparatus comprising:

(a) means for receiving a signal;

(b) means for determining a signal-to-noise ratio of the signal;

(c) means for determining whether a quick paging channel is transmitted at a half rate or a full rate; and

if the signal-to-noise ratio falls within a predetermined range, and if the quick paging channel is transmitted at the full rate;

(d) means for demodulating a first quick paging bit from the quick paging channel received through both a first receive chain and a second receive chain.

6. The apparatus of claim 5, further comprising:

if the signal-to-noise ratio is above the predetermined range, and if the quick paging channel is transmitted at the full rate;

(e) means for providing no power to the second receive chain; and

(f) means for demodulating a second quick paging bit from the quick paging channel received through the first receive chain.

7. The apparatus of claim 5, further comprising:

if the signal-to-noise ratio is below the predetermined range, and if the quick paging channel is transmitted at the full rate;

(e) means for providing no power to the second receive chain; and

(f) means for demodulating a general paging message from a regular paging channel received through the first receive chain.

8. The apparatus of claim 5, wherein the signal-to-noise ratio is the signal-to-noise ratio of a pilot channel.

9. A processor-readable media for storing instructions operable in a wireless device to:

(a) receive a signal;

(b) determine a signal-to-noise ratio of the signal;

(c) determine whether a quick paging channel is transmitted at a half rate or a full rate; and

if the signal-to-noise ratio falls within a predetermined range, and if the quick paging channel is transmitted at the full rate;

(d) demodulate a first quick paging bit from the quick paging channel received through both a first receive chain and a second receive chain.

10. The processor-readable media of claim 9, and further for storing instructions operable in a wireless device to:

if the signal-to-noise ratio is above the predetermined range, and if the quick paging channel is transmitted at the full rate;

(e) provide no power to the second receive chain; and

(f) demodulate a second quick paging bit from the quick paging channel received through the first receive chain.

11. The processor-readable media of claim 9, and further for storing instructions operable in a wireless device to:

if the signal-to-noise ratio is below the predetermined range, and if the quick paging channel is transmitted at the full rate;

(e) provide no power to the second receive chain; and

(f) demodulate a general paging message from a regular paging channel received through the first receive chain.

12. The processor-readable media of claim 9, and further for storing instructions operable in a wireless device, wherein the signal-to-noise ratio is the signal-to-noise ratio of a pilot channel.